A walking-beam conveyor, such as described in my copending patent application Ser. No. 868,339, filed Jan. 10, 1978, has at least one horizontally extending fixed beam and at least one horizontally extending movable beam parallel to the fixed beam. The movable beam can be stroked horizontally and vertically in a raise-advance/ /lower-return sequence of motions. Thus an object to be transported that is standing on the beams is lifted by the movable beam, advanced a step horizontally, and redeposited on the fixed beams. Typically a single movable beam is provided between a pair of fixed beams for safest supporting of the object beam transported. Such a conveyor can normally transport much heavier loads than a belt-type conveyor, and is particularly useful in a rolling mill or the like where the objects to be transported are not only extremely heavy, but relatively durable.
Thus it is standard practice in a rolling mill to provide such a walking-beam conveyor between adjacent treatment stations, as for instance extending from the winding station at the downstream end of one treatment path and to an unwinding station at the upstream end of another treatment path. Such winding and unwinding stations normally have horizontally extending spindles that must be fitted through the coil.
It is standard practice to use a separate conveyor carriage for displacing the coils at each end of the walking-beam conveyor from the winding or unwinding spindle on to the end of the conveyor. Even when the winding or unwinding spindle is provided directly at one end of the conveyor, it is normally necessary to provide a special mechanism for lifting the coil off or onto the spindle from the conveyor end, as obviously the spindle must be spaced a distance above the upper surface of the conveyor which is at least equal to the radius of the largest coil likely to be handled.
As the coils of sheet metal in a rolling mill are frequently of a diameter as great as 1.0 m-2.5 m, it is therefore necessary that the handling equipment for moving the coils from a windup or unwind spindle to the end of the conveyor be relatively large. This device is normally constituted as a self-powered vehicle which must be heavy-duty enough both to transport the coil horizontally through a predetermined distance, and to lift it vertically between the relatively high position of the spindle it is to be mounted on or removed from, and the relatively low position of the conveyor support surface. As the vertical stroke of the movable beam of the conveyor is only between 150 m and 200 m, even if the coil is picked off or set on to the conveyor when it is in its uppermost condition, it is still necessary to vertically displace the coil through some distance to move from the spindle to the conveyor or from the conveyor to the spindle. Consequently this relatively heavy-duty machine is expensive and adds appreciably to production costs of such a rolling mill. cl OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved walking-beam conveyor.
Another object is the provision of such a conveyor which overcomes the disadvantages of the above-described prior-art system.